Microsatellite analyses across three diverse vertebrate transcriptomes (Acipenser fulvescens, Ambystoma tigrinum, and Dipodomys spectabilis).

Historically, many population genetics studies have utilized microsatellite markers sampled at random from the genome and presumed to be selectively neutral. Recent studies, however, have shown that microsatellites can occur in transcribed regions, where they are more likely to be under selection. In this study, we mined microsatellites from transcriptomes generated by 454-pyrosequencing for three vertebrate species: lake sturgeon (Acipenser fulvescens), tiger salamander (Ambystoma tigrinum), and kangaroo rat (Dipodomys spectabilis). We evaluated (i) the occurrence of microsatellites across species; (ii) whether particular gene ontology terms were over-represented in genes that contained microsatellites; (iii) whether repeat motifs were located in untranslated regions or coding sequences of genes; and (iv) in silico polymorphism. Microsatellites were less common in tiger salamanders than in either lake sturgeon or kangaroo rats. Across libraries, trinucleotides were found more frequently than any other motif type, presumably because they do not cause frameshift mutations. By evaluating variation across reads assembled to a given contig, we were able to identify repeat motifs likely to be polymorphic. Our study represents one of the first comparative data sets on the distribution of vertebrate microsatellites within expressed genes. Our results reinforce the idea that microsatellites do not always occur in noncoding DNA, but commonly occur in expressed genes.

Fat dogs and coughing horses: K-12 programming for veterinary workforce development.

Workforce development strategies to educate, inform, and diversify the veterinary profession of the future must begin with children in elementary school. This article provides a description of the Fat Dogs and Coughing Horses program, which takes a multifaceted approach toward informing young students, beginning in first grade, about the interesting work and career opportunities available in the field of veterinary medicine. The program, a collaboration among Purdue University and Indiana public schools, is supported by a Science Education Partnership Award from the Office of Research Infrastructure Programs, a component of the National Institutes of Health. The overall goal of the program is to provide formal and informal educational opportunities for students, parents, teachers, and the public about the science involved in keeping people and their animals healthy. Examples of health concerns that impact both people and their pets are used to inform and excite children about careers in the health sciences. The program resulted in (1) curricula for students in Grades 1-3, 6, and 9; (2) four children's books and a set of collectible cards which highlight veterinarians, veterinary technicians, and research scientists who work with animals; and (3) four traveling museum-level quality exhibits. Preliminary assessment data has shown that the implementation of the curricula enhanced student science learning and science attitudes and interests. The program provides evidence that partnerships among professionals in veterinary medicine and K-12 education can result in impactful workforce development programs.

Comparative transcriptomics and gene expression in larval tiger salamander (Ambystoma tigrinum) gill and lung tissues as revealed by pyrosequencing.

Biologists are beginning to unravel the complexities of gene expression in model organisms by studying the transcriptome, the complement of genes that are transcribed in a given tissue. It is unclear, however, if findings from model systems apply to non-model organisms because of environmental effects on gene expression. Furthermore, there have been few efforts to quantify how transcriptome or gene expression varies across individuals and across tissues in natural environments. Herein, we describe transcriptomic profiling of gene expression in lung and gill tissue of three larval tiger salamanders. We do so with a hierarchical experimental design that captures variation in expression among genes, among tissues, and among individuals. Using 454 pyrosequencing, we produced high-quality sequence data of 59 megabases and assembled ~200,000 reads into 19,501 contigs. These contigs BLASTed to 3,599 transcripts, of which 721 were expressed in both tissues, 1,668 were unique to gill, and 1,210 unique to lung. Our data showed tissue-specific patterns in gene expression level with variation among transcripts and individuals. We identified genes and gene ontology terms related to respiration and compared their relative expression levels between gill and lung tissues. We also found evidence of exogenous genes associated with larval salamanders, and we identified ~1400 potential molecular markers (microsatellites and single nucleotide polymorphisms) that are associated with expressed genes. Given the tissue-specific differences we observed in transcriptomes, these data reinforce the idea that changes in gene expression serve as a primary mechanism underlying phenotypic plasticity.